The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Hockey criticised for US trip by Labor

A Labor frontbencher says Treasurer Joe Hockey should have been in the cabinet room last week rather than enjoying his jaunt in the United States that included ringing the bell at the end of trading on the New York Stock Exchange.

Mr Hockey was in the US for G20, the International Monetary Fund and the World Bank, gatherings the treasurer says will help him form his May 12 budget.

"The treasurer this week looked like the happiest bell ringer since Quasimodo ... when he should have been in the cabinet room ... working out a credible path for this budget," Labor's employment spokesman Brendan O'Connor told Sky News.